I try to install Pywikibot with git, following https://www.mediawiki.org/wiki/Manual:Pywikibot/Development and  https://www.mediawiki.org/wiki/Gerrit/Tutorial
When it comes to git clone, I keep getting this:

Cloning into 'core'...
fatal: unable to access 'https://gerrit.wikimedia.org/r/pywikibot/core.git/': SSL certificate problem: certificate has expired

Is it possible? I can't believe. Or is there another problem causing this message?
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